Missing Gmail emails since TMobile Froyo updateSupport

So, yesterday I happily installed the Froyo update from T-Mobile (which it later emerged was the German one). Nonetheless, everything seemed OK, and other than having to reinstall the Swype BETA to get it working I was quite happy playing around with the phone's new features etc.

Today I started having problems with my work Exchange account (I was getting an 'unable to sync' error, although it was working OK first thing in the morning). I know there are a few network problems at work so I had originally put the problem down to this. However, my phone's now started to behave weirdly - Swype's stopped working properly again (it will allow me to use it as a conventional key-by-key keyboard but not to Swype).

More importantly, Gmail is missing a pile of emails from this afternoon/this evening that are there when I check gmail on my web browser, but aren't pulling down to my phone. It isn't throwing errors and allows me to refresh. More confusingly it's pulled down two of emails from within the period since it's stopped working (ie it isn't showing emails from 15:30 onwards - there should be about a dozen between then and now, but it has pulled one from 18:45).

Anyone got any ideas?
______________
EDIT
Just checked through my account again and realised that my phone is now hiding anything with a label - I CAN see my 'missing' messages if I go to

> MENU > Go to labels > [Label]

I use my Gmail account as an 'aggregator' account, autoforwarding messages from several other accounts into Gmail and tagging them accordingly. Up until 08:40 this morning my inbox contains a mixture of direct Gmail messages, plus ones from the other accounts. They all have an 'Inbox' label, and those sent to my other accounts will also have another visible label (Work, Personal, etc). Messages received with labels since this morning are now ONLY visible if I filter to that label and not in the main Inbox. I haven't touched any settings at all and this definitely wasn't the behaviour before (i've got a load of older labelled messages in my inbox to prove it!).